Recently, in the field of wireless LAN (local area network) system, there has been developed a system which employs the Bluetooth system for carrying out processing in conformity with the frequency hopping system using a radio wave of a band of 2.4 GHz and carrying out transmission/reception of data between equipments.
The Bluetooth system is a system for realizing ad hoc radio (RF) networking between a plurality of personal computers and devices, which is being cooperatively developed by corporations of various industries such as computers, telecommunication, networking and so on, utilizing the radio communication technology. The Bluetooth system was planned by the Bluetooth SIG (Special Interest Group) in which the following corporations have taken part: Intel, Ericsson, IBM, Nokia, and Toshiba (trademark registered). The Bluetooth system enables a notebook computer, a PDA (personal digital assistant), or a portable telephone to share information and various services with a personal computer through radio communications, and makes troublesome cable connection unnecessary. Such Bluetooth system is disclosed in “Bluetooth (TM) Special Interest Group, Bluetooth specification version 1.0”.
Since the Bluetooth system is designed for ad hoc short distance connection, a standard communication range is within 10 m. According to the Bluetooth system, a “piconet” with the maximum number of connected devices equal to 8 and the communication range of 10 m is constructed by carrying out ad hoc multi-point connection, and a bandwidth of 1 Mbps is shared. In carrying out synchronous communication in accordance with the Bluetooth system, a transfer rate of 432.6 Kbps can be realized for both up communication and down communication, and therefore a rate approximately 10 times that of ordinary analog connection using a 56 K modem can be realized. On the other hand, in asynchronous communication in accordance with the Bluetooth system, communication at a higher speed is possible, and 721 Kbps for down communication and 57.6 Kbps for up communication are realized. Furthermore, the Bluetooth system also supports audio communication and enables setting of a maximum of 3 synchronous audio channels (at a transfer rate of 64 Kbps) at the same time. Simultaneous transfer of audio and data can be realized in one channel which provides a 64-Kbps synchronous audio link and an asynchronous data link. Such Bluetooth system can be used on various types of platforms and can realize radio communication at a low cost.
According to such Bluetooth system, an intelligent mechanism held by PC-based software can be realized in all kinds of electronic equipments. However, to realize practical application of the Bluetooth system, it is necessary to realize miniaturization and reduction in cost of transceiver components so as to incorporate them into the current notebook personal computers, PDA, portable telephones, portable head sets or the like. Since portable equipments normally use batteries, it is necessary to reduce the dissipation power.
In order to solve these problems, the Bluetooth system employs a system for compactly designing all logics and transceiver hardware. The transceiver hardware uses a radio frequency in a band of 2.4 GHz that can be used without permission and employs a diffusion system based on frequency hopping in order to prevent wire tapping and interference. In this frequency hopping, hopping is carried out 1600 times per second on 79 channels obtained by splitting the band every 1 MHZ (2.402 to 2.480 GHz). Also, according to the Bluetooth system, data is encrypted and devices that can access data are limited by password authorization, in order to improve the security of data transmission.
In a wireless LAN system 1100 employing the Bluetooth system as described above, wireless LAN modules 1110 of the Bluetooth system are mounted on a portable telephone 1101, a personal computer 1102, a digital camera 1103, and a portable information terminal 1104, respectively, as shown in FIG. 31. Thus, the portable telephone 1101, the personal computer 1102, the digital camera 1103 and the portable information terminal 1104 constituting the wireless LAN system 1100 can carry out transmission/reception of data between one another by carrying out transmission/reception of data using their respective wireless LAN modules 1110.
When connecting from the portable telephone 1101 of the wireless LAN system 1100 to the Internet 1300 via a mobile communication network 1200 by dial-up access, an Internet service provider 1301 in the Internet 1300 is accessed by the personal computer 1102, the digital camera 1103 or the portable information terminal 1104 via the wireless LAN system 1100 and the mobile communication network 1200, and connection to a WWW (world wide web) server 1302 in the Internet 1300 is made.
In this manner, with the wireless LAN system 1100, the personal computer 1102, the digital camera 1103 and the portable information terminal 1104 can be connected to the Internet 1300 through radio connection without having wired connection with the portable telephone 1101. Therefore, with the wireless LAN system 1100, the portability of the personal computer 1102, the digital camera 1103 and the portable information terminal 1104 can be improved. Also, with such wireless LAN system 1100, it is possible to connect to the Internet 1300 in the state where the user has the portable telephone 1101 in his/her bag and only carries a terminal such as the portable information terminal 1104 in hand.
The structure of a host equipment 1500 constituting the wireless LAN system 1100 will now be described with reference to FIG. 32. The host equipment 1500 is equivalent to an equipment operated by the user of the personal computer 1102, the digital camera 1103 or the portable information terminal 1104 of FIG. 31.
The host equipment 1500 is constituted by a communication control section 1510 which controls communication with the outside and is equivalent to the wireless LAN module 1110, and a host control section 1530 for controlling the equipment itself.
The communication control section 1510 has a radio communication unit 1511 for controlling radio communication within the wireless LAN system 1100, an antenna section 1512 for carrying out transmission/reception of data to/from each section constituting the wireless LAN system 1100, a base band control section 1513 for giving a hopping frequency pattern to the radio communication unit 1511, and an interface section 1514 for carrying out input/output of data with the host control section 1530.
The base band control section 1513 carries out modulation and demodulation processing of frequency hopping, processing for converting data handled in the communication control section 1510 into a predetermined format and transmitting the data via the communication control section 1510, and data conversion for converting the data received in the predetermined format and outputting the data to the host control section 1530.
The radio communication unit 1511 has a receiving section 1521 for carrying out processing for receiving data from the antenna section 1512, a transmitting section 1522 for carrying out processing for transmitting data from the antenna section 1512, a switch section 1523 for switching transmission of data from the transmitting section 1522 via the antenna section 1512 and output of data from the antenna section 1512 to the receiving section 1521, and a hopping synthesizer section 1524 for carrying out spectrum spreading based on frequency hopping with respect to the data in the receiving section 1521 and the transmitting section 1522.
Moreover, the communication control section 1510 has a RAM (random access memory) 1516, a ROM (read only memory) 1517, and a radio communication CPU (central processing unit) 1518 which are connected to a data bus 1515.
The radio communication CPU 1518 reads a control program for controlling each section constituting the communication control section 1510 from the ROM 1517 via the data bus 1515, thus generating a control signal. In this case, the radio communication CPU 1518 houses data into the RAM 1516 as a work space when necessary, and executes the control program. Thus, the radio communication CPU 1518 controls the base band control section 1513 and the radio communication unit 1511 so as to control communication with another equipment constituting the wireless LAN system 1100, and also controls the host control section 1530 via the interface section 1514.
The host control section 1530 in the host equipment 1500 has an interface section 1531 for carrying out input/output of signals with the interface section 1514 of the communication control section 1510. In the host control section 1530, a network setting storage section 1533 for storing network setting information such as the server address of the Internet service provider 1301 when the host equipment 1500 is connected to the Internet, an individual information storage section 1534 for storing individual information such as the mail address, password and the like of each user held by each host equipment 1500, and a CPU 1535 for controlling these sections are connected via a data bus 1532.
In such host equipment 1500, when connecting to the Internet 1300, first, the network setting information stored in the network setting storage section 1533 and the individual information stored in the individual information storage section 1534 are outputted to the communication control section 1510, and then, the radio communication unit 1511 and the base band control section 1513 are controlled so that connection setting with the Internet 1300 is carried out by the radio communication CPU 1518 of the communication control section 1510 using the network setting information and the individual information, thus establishing connection between the host equipment 1500 and the WWW server 1302.
To add the wireless LAN function of the Bluetooth system to each equipment, two techniques are considered. The first technique is to provide the wireless LAN function as a built-in function in the equipment, and the second technique is to store the wireless LAN function of the Bluetooth system on a PCMCIA (Personal Computer Memory Card International Association) card and connect it to another equipment.
FIG. 33 shows protocol stacks 1610, 1620 mounted on the portable telephone 1101 and the portable information terminal 1104 in connecting to the Internet 1300 by using the wireless LAN system 1100 having the wireless LAN function of the built-in type according to the first technique.
The protocol stack 1610 and the protocol stack 1620 have a physical layer (PHY), a media access control layer (MAC) and a logical link control layer (LLC) for realizing the wireless LAN system 1100 of the Bluetooth system, as lower three layers. Using the protocols of these lower three layers, the portable telephone 1101 and the portable information terminal 1104 carry out transmission/reception of data within the wireless LAN system 1100.
On the layer above the LLC of the protocol stack 1620, PPP (point to point protocol) is mounted, having a protocol necessary for dial-up access to the Internet 1300. On the layers above the PPP, IP (Internet protocol) and TCP (transmission control protocol) necessary for connection to the Internet 1300 are mounted, and an application layer (AP) for preparation of user data is further mounted.
In the protocol stack 1610, the protocols for realizing the Bluetooth system are mounted as the lower three layers similar to those of the protocol stack 1620, and a layer for using the mobile communication network such as W-CDMA (wide band-code division multiple access) or the like is mounted thereon, thus setting a data communication mode to realize connection to the Internet 1300 via the mobile communication network 1200.
FIG. 34 shows protocol stacks 1610, 1630, and 1640 mounted on the portable telephone 1101, the PCMCIA card 1105, and the portable information terminal 1104 in storing the wireless LAN function onto the PCMCIA card to realize the wireless LAN system 1100 according to the second technique.
The wireless LAN function for constructing the wireless LAN system 1100 of the Bluetooth system is built in the PCMCIA card 1105, and a physical layer (PHY), a medium access control layer (MAC) and a logical link control layer (LLC) for realizing the Bluetooth system are provided as lower three layers, similarly to the protocol stack 1610 of the portable telephone 1101. In the protocol stack 1630 of the PCMCIA card 1105, PCMCIA I/F is mounted as the upper layer above the LLC.
In the protocol stack 1640 of the portable information terminal 1104, PPP, IP, and TCP are mounted as the upper layers above the PCMCIA I/F layer, and AP and transmission/reception of user data are provided as the uppermost layer.
However, the first technique and the second technique for constructing the wireless LAN system 1100 as described above have the following problems.
That is, in the first technique, since the protocol stacks for realizing the wireless LAN system 1100 must be built in the equipments 1101, 1104 constituting the wireless LAN system 1100, the burdens on the equipments in terms of hardware and software are increased, complicating the equipments 1101, 1104.
Specifically, to provide the built-in wireless LAN function, it is necessary to mount the wireless LAN module 1110 on the equipments 1101, 1104, and also to mount various protocols for connection to the Internet 1300 on the equipment 1104 as shown in FIG. 33. Thus, in the first technique, the cost for manufacturing the equipments 1101, 1104 is increased and their designs are often redundant for users who do not make connection to the Internet 1300.
In the second technique, though connector joint with the equipments 1101, 1105, 1104 constituting the wireless LAN system 1100 can be realized by mounting the wireless LAN function on the PCMCIA card 1105, it is necessary to mount various protocols for connection to the Internet 1300 on the equipment 1104 as shown in FIG. 34 and there is also a problem of cost similar to that of the first technique. Moreover, since the PCMCIA card 1105 employs a parallel interface in the form of bus, the casing of the equipment 1104 on which the PCMCIA card is mounted is increased in size, making it difficult to apply the card to a small-size portable equipment.
Furthermore, the equipments 1101 to 1104 constituting the wireless LAN system 1100 need to store the network setting information and the individual information such as the address of the Internet service provider 1301, mail address, password and the like in connecting the Internet 1300, into the network setting storage section 1533 and the individual information storage section 1534, as shown in FIGS. 31 and 32.
Therefore, the user must set the network setting information and the individual information for each of the equipments 1101 to 1104, and with a portable equipment having a poor man-machine interface function, the operation for setting the network setting information and the individual information is troublesome and generates a large burden.
Particularly, when carrying out processing for changing the Internet service provider 1301 or the like, it is necessary to change the setting related to network connection of each of the plurality of equipments 1101 to 1104 constituting the wireless LAN system 1100.